Let me just say right off the bat that the Krell S-550i integrated amp displayed the chameleon-like character that is the signature of many of the great high end products on the market. It had a way of adapting to the source and allowing each performance to take on its own signature character. That is not to say that the Krell was lacking in its own innate character. The Krell had a number of very positive qualities that showed up in my notes over and over again.

The Krell S-550i's most obvious qualities were a three dimensional layering, a vibrancy and a grain-free response with an unyielding grip on the speakers.

A good example where all these qualities can be heard is on the recent SACD re-release Pink Floyd's Wish you Were Here. I listened to the original vinyl so much I wore out the grooves. This is not meant to be a cliché, I literally did. In this particular case though, I listened to the SACD's stereo track over the Sonus faber Venere 3.0's.

Tracks like "Shine on You Crazy Diamond" not only had the aforementioned 3d quality, but they also passed a lot of inner detail; details like being able to pick out the sound of the sax keys even in the louder passages. Elsewhere, I heard a solid foundation in the bass, great clarity in the mids and a transparent treble. There was no sense of strain and great dynamics throughout.

On the point of the treble, it at first may come across as a bit recessed or soft, but on further listening, I found it was just so very smooth and so very free of grain that it simply sounded recessed in comparison with amps that have an artificial edge in the treble.

After listening to the whole Pink Floyd album, I wrote "Man, if I'd have had this system when I was in college, I wouldn't have graduated. Ever."

Another good example of the vibrant and three dimensional sound was heard in the 180 gram reissue of the Steve Miller Band Greatest Hits 1974-78 album that I found on closeout at a Target store (?). This is such a great album with not a weak song on there.

I marveled at the vibrant and 3d presentation again. The amp's vibrant quality was most revealed through the texture of the guitar strings. But it went further than that. I enjoyed cymbal sounds with a natural structure and the timing of each note was impeccable. Bringing to mind that the Krell S-550i does put you in a slightly closer than neutral perspective to the performers.

Another strength of the Krell amp started to come to the fore and that was in the vocals. They had an "in the room with you sound" with no chestiness, nasality or excessive sibilants. It was incredible.

I needed to get to the bottom of this vocal thing, so I put on Melody Gardot The Absence also on vinyl. This is a great test for voice reproduction and this is one record where the stage extends way outside the confines of the speakers. As a modern recording, the bass is fuller and better defined, helping reveal the Krell's native character.

Ms. Gardot's voice was reproduced with so pure a tone it was almost unbelievable for Hifi. But the sound was just slightly too hyper for the recording and I felt close to the stage. Don't get the wrong idea as the sound was ethereal and had an understated elegance. I was thoroughly seduced and just sat back and simply enjoyed listening to the music.

I had yet another chance to be taken away by the music so much so that I had to keep reminding myself I was in the midst of a review. This time was while listening to Antonio Lysy at the Broad: Music from Argentina. I ripped this CD to my iPod and then played a compressed version through the Krell dock (320 kps). I do wish the iPod metadata would show up on the Krell's display because I can't read the info on an iPod from more than a few feet away and the Krell display was legible from my listening position.

Of course, the music was dynamically compressed due to ripping the music as an mp3 but the sound was still quite enjoyable. So I was once again tempted to just enjoy and I had to fight that urge. I was in the middle of a review after all.

My favorite parts of this album are when Antonio's cello solos are unaccompanied. But fuller arrangements could be emotive and the Krell did a bang up job with the piano in particular. There is an ease and naturalness to the sound. What I heard was clean, vibrant, and harmonically rich with extra smooth transitions between notes on the legato passages. Soft violin strings were refreshingly free of grain and noise.

In rounding out my listening impressions, I would like to share my experience with cinema. The new Warner Brothers release, Prisoners is just out on Blu-ray. This is a deeply troubling story starring Hugh Jackman and Jake Gyllenhaal.

I know Prisoners may not be everybody's first choice for review material but it is for me. The picture and sound are reference quality. There is a mesmerizing score, deep bass pulses, tons of atmospheric effects and plenty of voices both screaming and whisper soft. There is one scene where I swear you can hear the sound of a tree growing. It is in many ways the perfect test track.

I put the Krell S-550i in Theater Throughput mode to drive the main speakers. The other three satellites were being driven by an Emotiva XPA5 multi channel amp. There was clearly less noise in the mains than in the center speaker. The S-550i was able to preserve every minute detail in the audio from the softest to the loudest. This was heard mostly in the score, the deep bass pulses to set the mood and the most delicate of environmental effects. The Krell really pulled me in to the film maker's vision and I was entranced.